out of the corner of one's eye

out (of) the corner of (one's) eye

Of something seen, in one's periphery; partially and/or fleetingly, as opposed to fully and for an extended amount of time. Out the corner of my eye, I saw something moving in the bushes, and it turned out to be a stray cat. Sarah caught Tommy kissing Jessica out of the corner of her eye.
See also: corner, eye, of, out
Farlex Dictionary of Idioms.

out of the corner of one's eye

Glancing casually or surreptitiously, as in Out of the corner of my eye I saw Justin walking out the door. This expression refers to looking sideways at something rather than directly.
See also: corner, eye, of, out
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • out (of) the corner of (one's) eye
  • out of the corner of eye
  • out of the corner of your eye
  • from the corner of (one's) eye
  • like water off a duck's back
  • on the fringe
  • at (one's) doorstep
  • wet around the edges
  • moist around the edges
  • yes and no